I finally abandoned my email client last night. I have been using Pegasus, which is a very nice freeware client for Windows, and I have amassed a good store of emails in the database. It appeared to run fine under Wine, but I was wrong. Wine unceremoniously shuts it down every time I send a new message. Can't have that.
I looked at several replacement clients and finally settled on Evolution. It is not ideal, but it works well enough. I tried Sylpheed at the suggestion of jawtheshark but it's a little too minimalistic for my tastes.
The tether has been cut. Windows is still loaded on my other hard drive, but there's little motivation to go there now except when there are data files that I need to pull over, and that's happening less and less.